The present invention is concerned with planispheres. More particularly, the present invention is concerned with a planisphere built into a watch.
Planispheres comprise a polar projection of a celestial sphere and stars on a plane with adjustable circles or other appendages for showing celestial phenomenon for any given time. There exist a number of plastic and paper planispheres. These typically consist of paper or plastic discs with die-cut thumb wheels. The discs are rotated with the thumb and aligned with the time printed on a paper or plastic top card in order to reveal the orientation of the celestial bodies at that given time. Planispheres are made separately for the Northern and Southern hemispheres as the perspective of the viewer is different on either hemisphere.
However, there currently does not exist a planisphere which is incorporated into a watch. The present invention fulfills this need and provides other related advantages.
The present invention resides in a planisphere which is incorporated into a watch. The planisphere watch generally comprises a watch case including a transparent lens. A time keeping mechanism is disposed within the case and has a time display viewable through the lens. The time keeping mechanism and the time display can be any one of various types as known in the art, although in a particularly preferred embodiment, the time display comprises a minute hand and a hour hand overlying a dial.
Planisphere indicia, comprising a map of star constellations and star systems, is either imprinted onto the lens or onto the dial so as to be viewable through the lens. The dial may be coated with a luminescent material to facilitate viewing of the planisphere.
A tension ring surrounds the lens and has date indicia thereon. The date indicia comprises the months of the year in sequence around the ring, and preselected dates of each month.
A movable bezel overlies the lens and defines a window through which a portion of the planisphere indicia is viewed. The bezel includes time indicia, typically consisting of the hours of 6 P.M. through 6 A.M., spaced from one another, alignable with the date indicia of the tension ring. The bezel includes an aperture alignable with a month of the tension ring, and preferably a series of circumferential apertures, each aperture being aligned with a month of the tension ring. The bezel also includes directional information for orienting the planisphere indicia relative to the night sky.
Upon rotating the bezel to align the selected time indicia of the bezel with the selected date indicia, the planisphere indicia viewable in the night sky at the selected time and date is viewable through the bezel window. The user of the invention can orient himself or herself using the directional information imprinted on the bezel and compare the planisphere map of the watch to the star constellations visible at that particular time of that particular night of the year.
Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.